Does c# support hook a system event?

[anamnesis]

Thanks

[VegetableBird]

C#和.Net Framework中没有直接提供消息钩子的方法，但是可以通过API函数和非托管内存访问机制来实现。

你可以参考以下的步骤：

1、声明一个钩子函数代理：
public delegate IntPtr HookProc(int nCode, IntPtr wParam, IntPtr lParam);

2、声明API函数：
[DllImport("user32.dll", CharSet=CharSet.Auto)]
public static extern IntPtr SetWindowsHookEx(int hookid, HookProc pfnhook, IntPtr hinst, int threadid);

[DllImport("user32.dll", CharSet=CharSet.Auto, ExactSpelling=true)]
public static extern bool UnhookWindowsHookEx(IntPtr hhook);

[DllImport("user32.dll", CharSet=CharSet.Auto, ExactSpelling=true)]
public static extern IntPtr CallNextHookEx(IntPtr hhook, int code, IntPtr wparam, IntPtr lparam);

[DllImport("kernel32.dll", ExactSpelling=true, CharSet=CharSet.Auto)]
public static extern int GetCurrentThreadId();

public const int WH_MSGFILTER = -1;


3、写你自己的HookProc代理实现方法，如MyHookProc
public IntPtr MyHookProc(int nCode, IntPtr wParam, IntPtr lParam)
{
//...你的代码
return CallNextHookEx(iHookHandle, code, wparam, lparam);
}

4、为你的类声明一个Hook Handle和非托管的钩子线程地址：
private IntPtr _iHookHandle=IntPtr.Zero;
private GCHandle _hookProcHandle;

5、在合适的地方安装你的钩子
HookProc hookProc = new HookProc(MyHookProc);
_hookProcHandle = GCHandle.Alloc(hookProc);
iHookHandle = SetWindowsHookEx(WH_MSGFILTER, hookProc, IntPtr.Zero, .GetCurrentThreadId());
if (iHookHandle == IntPtr.Zero) throw new System.Exception("没有足够权限安装钩子！");

6、在合适的地方卸载你的钩子
if (iHookHandle!=IntPtr.Zero)
UnhookWindowsHookEx(iHookHandle);
_hookProcHandle.Free();
iHookHandle = IntPtr.Zero;

[anamnesis]

thanks
给分